Ground Excavation Preparation System

ABSTRACT

A ground excavation preparation apparatus for thawing a frozen ground surface prior to excavation, consisting of a trailer; a housing connected to the trailer; mobility means attached to the trailer for moving the apparatus; heat generation means above the housing for supplying thawing energy; heat distribution means within the housing for transferring heat into the ambient air within the housing; and hydraulic means connecting the trailer to the housing for raising and lowering the housing at an excavation site.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to heavy equipment. In particular, thepresent invention relates to an apparatus for preparing terrain forexcavation.

BACKGROUND OF THE INVENTION

It is common in carrying out infrastructure and industrial projects forthere to be a need to dig into the ground at an excavation site. Variousprior art technologies exist for such excavation. However, suchexcavation may be impractical, extremely difficult or impossible undercertain circumstances.

One example of such circumstances is extremely cold weather whichresults in freezing of the ground surface and underlying material. Forex ample, a utility line may need to be repaired under a frozen pavedstreet.

It is desirable to prepare the excavation site for excavation bythorough ground thawing. Prior art methods have used propane tanks as asource of fuel to thaw the frozen ground, but such tanks requirefrequent refilling. The present invention provides a mobile, efficient,safe apparatus for ground excavation preparation.

SUMMARY OF THE INVENTION

There is provided a ground excavation preparation apparatus consistingof a trailer; a housing connected to the trailer; mobility meansattached to the trailer for moving the apparatus; heat generation meansabove the housing for supplying thawing energy; heat distribution meanswithin the housing for transferring heat into the ambient air within thehousing; and hydraulic means connecting the trailer to the housing forraising and lowering the housing at an excavation site.

The housing may be a rectangular, open-bottomed box of between 6 and 10feet wide, preferably 8 feet wide, and between 12 and 30 feet long,preferably 20 feet long.

The mobility means may comprise a frame and hitch assembly forconnection of the apparatus to a towing vehicle, and a wheel assemblyhaving at least one pair of wheels joined by an axle, the assemblypivotally connected to the second end of the housing.

The heat generation means may comprise a diesel burning unit and adiesel fuel storage tank. The heat distribution means may comprise heattransfer piping within the housing having a first end connected to theheat generation means and a second end connected to an exhaust pipe. Theheat transfer piping may be between 45 and 90 feet, preferably 65 feetlong. The heat transfer piping may have a diameter of between 8 and 12inches, preferably 10 inches, and the exhaust pipe may have a diameterof between 2 and 6 inches, preferably 4 inches.

The hydraulic means may comprise an engine and a hydraulic pump forlowering and raising the housing at an excavation site.

There is further provided a method of ground excavation preparationcomprising the steps of: transporting a ground excavation preparationapparatus as described herein to a site; lowering the housing byhydraulic means until the housing rests on the surface of the ground,forming an enclosed space within the housing above the ground surface;starting the diesel burning unit to generate hot exhaust distributioninto the heat transfer piping and out the exhaust pipe to effect thawingof the adjacent ground surface; raising the housing by hydraulic means;transporting the apparatus away from the thawed site; and excavating thethawed site.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the preferred embodiments is provided by wayof example only and with reference to the following drawings, in which:

FIG. 1 depicts an end view of the ground excavation preparation systemof the present invention, showing the system in a lowered position forthawing;

FIG. 2 depicts a side view of the ground excavation preparation systemof the present invention, showing the system in a lowered position forthawing;

FIG. 3 depicts the ground excavation preparation system of the presentinvention, showing the system in a raised position after thawing, andshowing the thawed site ready for excavation; and

FIG. 4 depicts the underside of the housing, showing one embodiment ofthe piping pattern.

In the drawings, one embodiment of the invention is illustrated by wayof example. It is to be expressly understood that the description anddrawings are only for the purpose of illustration and as an aid tounderstanding, which are not intended as a definition of the limits ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

As depicted in the figures, the apparatus of the present inventioncomprises a trailer having a housing; mobility means; heat generationmeans; heat distribution means; and hydraulic means.

According to one embodiment, the housing may comprise an invertedrectangular open-bottomed metal box 2 approximately 8 feet wide, 20 feetlong, and 2 feet deep. Other box dimensions are also within the scope ofthe invention.

The mobility means may comprise, at a first end of the housing, a frame4 and hitch 6 assembly, as is know in the prior art, for reversibleconnection of the system to a towing vehicle for transportation of thesystem to and from an excavation site. At a second opposing end of thehousing, the mobility means may further comprise a wheel assembly 8,preferably having at least one pair of wheels joined by an axle, theassembly pivotally connected to the second end of the housing, wherebylowering of the wheel assembly effects raising of the second end of thehousing off of the ground and raising of the wheel assembly effectslowering of the second end of the housing to the ground.

The heat generation means preferably may comprise one or more dieselburning units 10 adjacent the housing and a fuel storage tank 11. Otherheat generation means are also within the scope of the invention.

The heat distribution means may comprise heat transfer piping 13 tocarry the heated exhaust generated by the diesel burning unit throughoutthe housing an directed towards the frozen ground surface. Preferably,the heat transfer piping is approximately 10 inches in diameter andapproximately 65 feet in length, extending in a path which traverses thelength of the housing approximately three times, ideally along eachlateral side and the middle of the housing, as depicted in FIG. 4. Theheated exhaust is vented through a vertical pipe 12 preferably having adiameter of 4 inches. The reduction in diameter of the exhaust piperelative to the piping within the housing slows the release of theheated exhaust, increasing heat transfer from the housing piping intothe surrounding air enclosed within the housing box, effecting thawingof the adjacent ground surface. Other piping and exhaust pie dimensionsare also possible and within the scope of the invention.

The hydraulic means may comprise an engine and hydraulic pump 14 forlowering the housing onto the ground surface at a desired excavationsite prior to ground thawing, and for raising the housing away from theground surface after ground thawing.

In operation, the ground excavation preparation apparatus is transportedto a site to be thawed, the housing is lowered to the ground, and thediesel burning unit is started. The hot exhaust generated within thepiping causes thawing of the adjacent ground surface below the housing.

Thawing of the ground surface may be achieved within 5 minutes ofoperation of the diesel burning unit. Once thawing is complete, thehydraulics may be used to raise the housing and the apparatus may bemoved from the prepared site to permit excavation manually or with theuse of excavation machines.

Thawing of a frozen asphalt surface will also melt the asphalt toconvert the asphalt to gravel to permit excavation. Accordingly, theapparatus of the present invention may also be used in non-frozenconditions to remove asphalt for excavation. The flat vertical sides ofthe housing pressing against the melting asphalt produce clean, straightvertical edges to the excavation site.

The system of the present invention thaws the ground only within thearea below the housing, leaving the surrounding area frozen. Thisreduces or eliminates the need for any showing of the surrounding areaor the use of trench cages.

It will be appreciated by those skilled in the art that other variationsof the preferred embodiment may also be practised without departing fromthe scope of the invention.

1. A ground excavation preparation apparatus comprising: a trailer; ahousing connected to the trailer; mobility means attached to the trailerfor moving the apparatus; heat generation means above the housing forsupplying thawing energy; heat distribution means within the housing fortransferring heat into the ambient air within the housing; and hydraulicmeans connecting the trailer to the housing for raising and lowering thehousing at an excavation site.
 2. The ground excavation preparationapparatus of claim 1, wherein the housing comprises a rectangular,open-bottomed box.
 3. The ground excavation preparation apparatus ofclaim 2, wherein the housing is between 6 and 10 feet wide, and between12 and 30 feet long.
 4. The ground excavation preparation apparatus ofclaim 1, wherein the mobility means comprises a frame and hitch assemblyfor connection of the apparatus to a towing vehicle.
 5. The groundexcavation preparation apparatus of claim 4, wherein the mobility meansfurther comprises a wheel assembly having at least one pair of wheelsjoined by an axle, the assembly pivotally connected to the second end ofthe housing.
 6. The ground excavation preparation apparatus of claim 1,wherein the heat generation means comprises a diesel burning unit and adiesel fuel storage tank.
 7. The ground excavation preparation apparatusof claim 1, wherein the heat distribution means comprises heat transferpiping within the housing having a first end connected to the heatgeneration means and a second end connected to an exhaust pipe.
 8. Theground excavation preparation apparatus of claim 7, wherein the heattransfer piping extends is between 45 and 90 feet long.
 9. The groundexcavation preparation apparatus of claim 7, wherein the heat transferpiping extends is approximately 65 feet long.
 10. The ground excavationpreparation apparatus of claim 7, wherein the heat transfer piping has adiameter of between 8 and 12 inches, and the exhaust pipe has a diameterof between 2 and 6 inches.
 11. The ground excavation preparationapparatus of claim 7, wherein the heat transfer piping has a diameter ofapproximately 10 inches, and the exhaust pipe has a diameter of 4inches.
 12. The ground excavation preparation apparatus of claim 7,wherein the heat transfer piping has a diameter at least 50% greaterthan the diameter of the exhaust pipe.
 13. The ground excavationpreparation apparatus of claim 1, wherein the hydraulic means comprisean engine and a hydraulic pump for lowering and raising the housing atan excavation site.
 14. A method of ground excavation preparationcomprising the steps of: transporting the ground excavation preparationapparatus of claim 1 to a site; lowering the housing by hydraulic meansuntil the housing rests on the surface of the ground, forming anenclosed space within the housing above the ground surface; starting thediesel burning unit to generate hot exhaust distribution into the heattransfer piping and out the exhaust pipe to effect thawing of theadjacent ground surface; raising the housing by hydraulic means;transporting the apparatus away from the thawed site; and excavating thethawed site.